Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/13/17
Area Forecast Discussion
National Weather Service La Crosse WI
638 PM CDT Mon Jun 12 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 259 PM CDT Mon Jun 12 2017
High Impact Weather Potential: Thunderstorm chances continue through
Wednesday night, particularly tonight and again later Tuesday night
into Wednesday. Isolated severe storms can`t be ruled out through
the evening and again overnight, as well as later Tuesday night
into Wednesday.
Steamy and active summertime setup across the local area at the
moment, with a frontal boundary draped just south of the I-90
corridor, nudged slightly today by a push of high pressure and
much drier air just to the north. That boundary has been and will
remain the focus for convective potential this evening through
tonight, with an earlier MCS to our west evolving into more of a
linear system the past few hours as additional convection slowly
unzips along the front. Deep shear remains fairly week, especially
as one works southeast from a max of 30 knots into southeast MN
and central WI, but with some lower level turning/shear near the
boundary. Have had a few reports of marginal severe hail/wind the
past hour, and suspect that convection will tend to propagate
east/northeastward the next few hours, perhaps continuing to
gradually redevelop east given plentiful instability up to 3000
J/kg. From a severe perspective, can`t totally rule out
something spinning along the boundary where 0-1km shear is around
20 knots per RAP trends, but would think the overall severe risk
will gradually truncate with eastward extent. Like the past few
days, any storms will be efficient rainers with PWAT values around
2 inches and slower storm movement given the lack of flow aloft.
As discussed yesterday, still thinking our "best" shot at a little
more widespread convection may come tonight as the warm front begins
to lift back northward. Axis of moisture transport pointed directly
into the region suggests the best low level jet forcing working into
our area, with continued limited capping and elevated CAPE values in
excess of 2000 J/kg. Shear is again limited but heavy rain threat
remains through the night, though it does appear storms will
increasingly be lifting north with time as the forcing does the same.
Thereafter, looks like we really get capped off on Tuesday as much
of the area breaks into the warm sector, with 700mb temps spiking to
13-15C. Good mixing with 925mb temps around 24-26C+ suggests another
windy and very warm day, with temps potentially very close to record
territory barring any lower stratus issues, which could present
themselves at some point near the warm front, especially near/north
of I-94. Otherwise, will be watching what happens to our west into
Tuesday evening and night with several bouts of mainly linear
convection likely to fire over the Central Plains ahead of a
stronger upper trough swinging east out of the Rockies. Good shear
out that way suggests organized storms are likely and may well
survive their eastward jaunt in our direction Tuesday night. Some
question remains about better forcing over this way, but a low end
risk for severe storms could exist later Tuesday night but
especially on Wednesday as we may see initial convection fall apart
but then redevelop with the heating of the day as the remnants of
the cold front arrive.
.LONG TERM...(Tuesday night through Monday)
Issued at 259 PM CDT Mon Jun 12 2017
Flow pattern continues to shift from one of weak upper ridging to
more of a flat flow aloft through late week, and then potentially
more upper troughing toward the weekend. Given that shift,
confidence in the details toward Thursday-Friday remains on the
lower side, but there have been persistent hints from guidance the
past few days for a passing shortwave and cold front to bring at
least a chance for showers and storms on Friday or Friday night.
Beyond that, the overall idea of cooler conditions for the weekend
looks well trended at this time, with maybe a smaller risk for some
showers at times given cooler air aloft and some passing weaker
waves. For the moment, the thunder threat continues to look low with
limited diurnal instability as all of the deeper moisture is at
least briefly punted back southward through the mid Mississippi
Valley. In simple terms, that means lower dew points for all -
doubtful anyone will complain about that!
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 638 PM CDT Mon Jun 12 2017
After another round of strong thunderstorms this afternoon, expect
a break in activity this evening at TAF airfields with VFR
ceilings and light wind. For the overnight hours, given nearly
saturated low-levels, expect some reductions in visibility due to
mist. Will keep MVFR ceilings late tonight into Tuesday morning,
although now confidence is not as high given some differing model
solutions. If lower ceilings develop, they should lift back above
3000 ft agl by 13.17Z. Light and variable wind through tonight
will increase somewhat and shift to the southeast on Tuesday,
gusting at times into the mid 20 kt range at KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Lawrence
LONG TERM...Lawrence
AVIATION...Rogers
Area Forecast Discussion
National Weather Service Des Moines IA
1050 PM CDT Mon Jun 12 2017
.UPDATE...
Issued at 629 PM CDT Mon Jun 12 2017
Convection has moved east of the watch and have cancelled the
watch. Additional convection may develop later this evening...
though will need to be evaluated again through the evening.
&&
.SHORT TERM.../Tonight through Tuesday/
Issued at 345 PM CDT Mon Jun 12 2017
The primary concern into Tuesday remains convective trends and
confidence is admittedly low. The remnants of the AZ/CO short wave
mentioned at this time yesterday was not handled well by the
models and resulted in a warm sector MCS removed from the boundary
farther north. Its remnants continue to drift through Iowa at 20z
with isolated storms lingering near its core. Various channels of
GOES 16 imagery nicely showed a circular gravity wave whose
northern arc interacted with increased convergence along the
synoptic boundary and developed another MCS currently moving
through the Upper MS Valley. The question becomes where or if
additional convection will form. Forecast soundings suggest any
additional convection that forms would have to be rooted fairly
low while the H85/H7 baroclinic zone pushes northward into the
Dakotas and MN. Thus the current outflow from the MN MCS may be a
key and is still fairly noted, through Storm Lake, Fort Dodge and
Mason City. The HRRR and ESRL HRRR seem to be following this
progression ok and suggest the isolated western IA convection may
linger into the evening followed by more development across
northern IA into the early morning hours just north of the
aforementioned outflow boundary. If any significant storms form
damaging wind and locally heavy rains would be the primary
threats, and large hail to a lesser extent due to the warm, moist
airmass. Convection allowing model solutions vary from unorganized
convection to a significant organized forward propagating wind
MCS so upstream trends from the Siouxland west will play a key and
need to be monitored.
By tomorrow most solutions end the convection with our forecast
area into the warm sector as both the baroclinic zone aloft and
shallow outflow boundaries retreat to the north. Am hesitant to
warm things up too much however based on recent verification so
have left the forecast near what has been typical for the past few
days with highs in the lower to middle 90s. The next round of
convection associated with the front and lobe of forcing to our
west should remove outside our forecast area through 00z so have
left the forecast dry through that time.
.LONG TERM.../Tuesday night through Monday/
Issued at 345 PM CDT Mon Jun 12 2017
The main forecast concern was focused on severe weather potential
Tuesday night into Wednesday and then temperatures and
precipitation chances mid to late week. Utilized a blend tomorrow
night into Thursday and then slightly leaned closer to the ECMWF
for the rest of the forecast period.
Tuesday night into Wednesday...Forecast area remains well in the
warm sector ahead of a cold front and associated upper level
trough to push into the state during this time frame. The better
focus for severe potential remains to the west of the forecast
area as initiation looks to be in portions of SD and even northern
NE. The most likely scenario is this convection to evolve and
transition into some sort of MCS moving across central to northern
Iowa Tuesday evening into Wednesday morning instead of storms
developing directly in the CWA. Even though there is plenty of
instability that builds into the state with surface based CAPE
ranging from 3000 to over 4000 J/kg by 00z Wednesday over much of
the state, there is a very strong cap will hold initiation in
check prior the aforementioned convection in SD moving into
forecast area. Thus, much of the convection (or at least severe
potential) tomorrow night looks to be mainly prior to sunset, if
these storms reach the CWA prior to sunset. The front looks to
become somewhat washed out as it moves eastward with time tomorrow
night into Wednesday, and losing any significant forcing
mechanism to trigger further convection. 0-6km bulk shear west of
Interstate 35 ranges around 25-30 knots or less, with the 0-3km
and 0-1km shear around 15-20 knots. Lapse rates do remain
moderately unstable tomorrow night, especially across western to
north-central Iowa. More confident in the heavy rain potential
that severe weather potential as warm layer cloud depths in the
13kft to 14kft range, decent moisture transport into the area,
precipitable water values in the 1.5 to 1.75 inches, and Corfidi
vectors weak and showing potential for backbuilding/training.
Although we`ve been dry lately and the area could take some rain,
the rainfall rates may be high enough to cause some flash flooding
potential tomorrow night.
Still looking at another warm and humid day on Wednesday with the
cold front remaining to the west of the forecast area. There is a
weak shortwave to cut across Missouri into eastern Iowa by the
afternoon hours Wednesday which provides some focus for severe
weather potential in the eastern portion of the forecast area.
Plus, if storms do develop, cloud debris will help keep
temperatures a little cooler than the ongoing forecast.
Thursday through Saturday...another above normal day on Thursday
with much of the area reaching the lower 90s again as a weak
surface ridge quickly moves east of the state and provides some
weak return flow into the state. Dew points remains in the middle
to upper 50s, so the heat index values and impacts will be
minimal. Somewhat cooler air by Friday and Saturday with highs
back into the 80s across the forecast area. Models diverge on any
significant shortwave to pass across the region and have low
confidence with any timing of pops at this moment.
&&
.AVIATION.../For the 06Z TAFS through 06Z Tuesday night/
Issued at 1050 PM CDT Mon Jun 12 2017
Main concern is overnight convection into early Tuesday.
Outflow boundary has drifted south to near KDSM Apt with both
upper/sfc moisture convergence. Some redevelopment near KDSM at
0345z may intensify and drift back north with south ambient wind.
Shear remains weak...so though storms may intensify...widespread
coverage with significant impacts not expected. Winds will
gradually become south again and increase with gusts 20 to 25kt by
15-17z. Whatever convection is leftover by 12-15z north will move
out of the forecast area for the remainder of the day with VFR
conditions expected. Late in the period another chance of thunder
will approach KFOD/KDSM mainly aft 14/02z. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...REV
SHORT TERM...Small
LONG TERM...Podrazik
AVIATION...REV
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
857 PM CDT Mon Jun 12 2017
.UPDATE...
The forecast is still on track, no changes other than re-trending the
grid forecasts through 12Z.
&&
.PREV DISCUSSION... /ISSUED 637 PM CDT Mon Jun 12 2017/
UPDATE...
00Z Aviation Update Below.
AVIATION...
VFR conditions will prevail through the evening hours. TSTMs across
West Texas are expected to dissipate after sunset, before reaching
the DRT area. MVFR stratus will develop 06Z-10Z across the region.
Some patchy IFR stratus is possible around the AUS area and over the
Hill Country around sunrise. VFR conditions will then re-develop
16Z-18Z.
Winds SE 7-12 kts this evening with a few gusts 15-20 kts through
sunset. Occasional gusts may continue at DRT into a portion of the
overnight. Winds subsiding at the I-35 sites to around 5 kts
overnight. Winds will strengthen to 10-15 kts by midday Tuesday with
gusts exceeding 20 kts during the afternoon.
PREV DISCUSSION... /ISSUED 249 PM CDT Mon Jun 12 2017/
SHORT TERM (Tonight through Tuesday)...
No major highlights in the short term weather-wise but the there
will a slight up-tick in sea-breeze activity tomorrow along and east
of I-35. Near normal temperatures are expected.
Per water vapor satellite channels and RAP analysis - a weak
trough/shear axis remains over the northwest Gulf of Mexico to the
upper Texas coast while a much stronger shortwave trough is located
over the western CONUS. Since south-central Texas is on the backside
of the weak trough in the Gulf and with weak ridging across the Rio
Grande Basin into Mexico, suppression of showers activity is
occurring. There is also a stout capping inversion over most of the
area, further adding confidence of limited to no rain chances today
for the coastal plains. Have decreased rain chances through the
afternoon with only very limited sea-breeze activity expected to make
into far eastern coastal plains. Greater coverage today will remain
east of the region towards TX/LA.
Overnight, expect low stratus clouds to return to the Hill Country and
into the Escarpment area. Farther south and east, patchy ground fog
will again be possible where the clouds do not fill in as much. This
has been the case the past few days. PWATs will increase from near
1.2" today to near 1.5" on average along and east of US Highway 281.
The added moisture for eastern areas plus indications of a weaker
capping inversion suggest Tuesday may be the best day for sea-breeze
showers and a few thunderstorms to occur. Expect scattered coverage
across the coastal plains with more isolated coverage towards I-35 as
it moves inland in the afternoon. Western areas will remain dry due
to mid-level ridging influence. Showers and thunderstorms could drop
a quick quarter to half inch but will likely not remain over one
spot too long.
LONG TERM (Wednesday through Monday)...
Drier and warming conditions expected mid- to late-week with above
normal temperatures expected. Heat indices will reach into the
100-105F range most areas (expect Hill County) through the week. A
pattern shift will occur late week and persist through the weekend
that could introduce additional rain and thunderstorm chances.
Models are in good agreement that low- and mid-level ridging will
build over south Texas Wednesday and partially into Thursday. This
should temper sea-breeze activity back down along with a slightly
stronger advertised capping inversion. By Thursday afternoon
however, mid-level H5 flow will switch from zonal to more of a NW
flow pattern while low-level (H85-H7) ridging attempts to hold on.
With this pattern shift and weaker capping to the north near the Red
River, will need to monitor for thunderstorm potential across far
north Texas and if it can ride the NW flow towards the region late
Thursday into Friday morning. While the probability appears low
currently, this pattern could support such convective evolution. By
Friday, stronger north to northwest flow will occur in the mid- and
upper-levels with steepening lapse rates. The passage of an upper
level trough looks to occur Friday afternoon. While there appears to
be a capping inversion potentially helping to prevent convection
Friday, the building CAPE and flow aloft could support showers and
storms if they were to break through the cap. Some storms could
become strong/severe if they break the cap or it weakens. Have only
placed a 20% chance of showers for now and will need to watch the
strength of the capping inversion.
By the weekend, the H5 ridging will be center north and west of south
Texas placing the area under a weak low-level inverted trough
pattern in easterly flow. This could enhance sea-breeze and
afternoon diurnal showers and thunderstorm activity, especially along
and east of I-35. Greater chances of rain will be for the south half
of the region closer to the inverted low convergence with slightly
greater ridging influence across the north half.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 73 92 75 94 75 / - 20 10 10 -
Austin Bergstrom Intl Airport 73 91 75 94 74 / - 20 10 10 -
New Braunfels Muni Airport 72 92 75 94 74 / - 20 10 10 -
Burnet Muni Airport 70 89 72 91 72 / 0 10 - - -
Del Rio Intl Airport 73 96 74 97 76 / 0 0 - - -
Georgetown Muni Airport 72 91 73 92 74 / - 20 - 10 -
Hondo Muni Airport 71 94 75 95 75 / 0 - - - -
San Marcos Muni Airport 72 92 75 94 74 / - 20 10 10 -
La Grange - Fayette Regional 74 91 75 93 75 / 10 30 10 20 -
San Antonio Intl Airport 73 93 76 94 76 / - 10 - 10 -
Stinson Muni Airport 73 93 75 95 76 / - 10 - 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Runyen
Synoptic/Grids...26
Public Service/Data Collection...Williams
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
620 PM CDT Mon Jun 12 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 228 PM CDT Mon Jun 12 2017
The main concerns in the short term period revolve around
thunderstorm potential, strong and severe, this afternoon and
evening. Latest satellite imagery shows sky cover eroding in
northeast CO to southwest NEB. Surface dew points at the top of
the hour range from the lower 60s to around 70, highest towards
south central NEB.
Latest SPC mesoanalysis shows strong instability with MLCAPE in
excess of 3000 J/kg from northeast CO and across the southern
Sandhills. There is some MLCIN. Soundings show an environment
featuring an elevated mixed layer over southwest NEB that is
providing some convective inhibition, especially farther east
across southwest NEB towards central NEB. Steep mid-level lapse
rates (700-500 hPa) are in place as well. Deep layer vertical
wind shear ranging near 40-50 kts and 200-250 m2/s-2 0-3 km SRH
upstream/far western portion of the CWA that show an environment
with potential for supercells. While there is some range with
solutions in hi-res guidance (comparing the SPC SSEO 00Z cycle,
flavors of wrf, HRRR, and HRRR experimental), a signal for
development in northeast CO/southern Panhandle into southwest NEB
is there. While they generally show storms weakening as they move
into southwest NEB, we are not completely confident with this
given instability and if storms have supercell features. As such,
the greatest uncertainty for storm develop/potential is in
southwest NEB. Current thinking also is this would be the most
likely area for more discrete storms given environment setup and
based on hi-res guidance. Thus the best chances for thunderstorms
and precip rest of today and tonight are along west and north of
a line from Grant to Ogallala to Mullen to Ainsworth. Elsewhere,
guidance have been fairly consistent with respect to northwest
NEB and t-storm chances haven`t changed much. Continue to think
storms/MCS will affect portions of northwest NEB this evening.
Overall, threats for storms include all hazards (large hail,
damaging winds, tornadoes). Though the best tornado potential
appears just outside the forecast area to the west this afternoon
and early evening, will continue to monitor as the day evolves.
Tomorrow, predominantly dry conditions will prevail though there
is potential for thunderstorm, mainly along and east of Highway
281. Near to slightly above normal highs will prevail tomorrow,
not that different from today.
.LONG TERM...(Tuesday night through Monday)
Issued at 228 PM CDT Mon Jun 12 2017
A few thunderstorms will be possible Tuesday evening across Boyd,
Holt, Garfield, and Wheeler Counties, some may be strong to severe
as a negatively tilted trough swings through the region. The best
moisture will be ahead of a cold front in eastern Nebraska by the
time the storms fire so whether or not our eastern counties see any
stronger activity will depend on the timing of this feature. There
is certainly enough shear and instability to support a stronger
storm or two.
Swift zonal flow takes over on Wednesday behind the exiting upper
low. We should not see any rain Wednesday through Friday. The next
chance will be this weekend as another system moves across the
northern tier of the US. Temperatures will dive back toward normal
and remain there for the week with highs in the 80s to near 90
across the south.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 620 PM CDT Mon Jun 12 2017
The extreme instability and severe thunderstorm threat should end
across Wrn Neb around 06z. Redevelopment is expected 21z-00z
Tuesday across ern Holt and Boyd counties. Otherwise VFR is
expected.
&&
.FIRE WEATHER...
Issued at 228 PM CDT Mon Jun 12 2017
Elevated fire weather conditions are expected tomorrow. Dry air
will move in and prevail across western Nebraska with afternoon
minimum relative humidity falling to 15 to 20 percent across
western Nebraska. Winds, however, are a limiting factor and will
be westerly 10 to 20 mph, strongest in northwest NEB tomorrow
afternoon.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...ET
LONG TERM...Allen
AVIATION...CDC
FIRE WEATHER...ET
Area Forecast Discussion
National Weather Service Lake Charles LA
724 PM CDT Mon Jun 12 2017
.UPDATE...
SHRA/TSRA was diminishing between 6 and 7 PM, but has re-
intensified along the I-10 corridor of S LA/SE TX. latest HRRR
guidance shows this continuing and spreading inland the next 2-3
hours, diminishing by midnight, with isolated showers to continue
overnight areawide. Thus, updated evening forecast for QPF,
chances of precipitation this evening to 50-60% for areas affected
now and the next 3 hours, diminishing to 20-30% between 10 PM-1
AM. Left 20% inland for isolated showers overnight, with activity
re-starting across the coastal waters during the predawn morning
hours.
DML
&&
.PREV DISCUSSION... /issued 642 PM CDT Mon Jun 12 2017/
DISCUSSION...
13/00Z TAF Issuance.
AVIATION...
Sctd TSRA persist late this aftn acrs the area but model guidance
indicates a decreasing trend through the evening as daytime
heating wanes. Residual SCT/BKN high-based CU and CI will linger
overnight but VFR conditions are expected to prevail. Expect sctd
SHRA/TSRA to develop again early Tuesday morning over the coastal
parishes and gradually spread inland toward the southern terminals
by 14-15Z. Convection will increase in coverage by midday
(although not quite as much as today), and carried PROB30 at all
sites after 18Z except for the Acadiana terminals where TEMPO
groups were inserted as highest chcs are expected here. Winds will
be light and southeasterly overnight, strengthening to 7-12 KT
during the day.
24
PREV DISCUSSION... /issued 419 PM CDT Mon Jun 12 2017/
DISCUSSION...
Upper low which was over SE TX yesterday has become ill-defined
and barely discernible in GOES-R imagery this afternoon, though a
well defined and relatively sharp MSTR gradient remains over E TX
and down into the WRN Gulf. GOES-R TPW product aligns with model
data in depicting 2+ inches over the entire forecast area, as a
long and steady fetch of tropical moisture continues to stream
into the region around a SFC/low level ridge over the SE CONUS/WRN
Atlantic.
Gradual changes are poised to begin that will gradually decrease
convective coverage over the next couple of days, though at least
small chances will remain through the forecast period. The low to
mid level ridge to the east is forecast to build a bit WWD, while
a ridge aloft over NRN MX/W TX builds eastward. The net effect
will be decreasing deep layer moisture and increasing mass
subsidence, though sufficient moisture/instability will persist
for primarily scattered afternoon and sea-breeze driven
convection. Temperatures will also creep upward, and are forecast
to reach around 90 each afternoon. Lows will continue in the
low/mid 70s.
13
MARINE...
Light to at times modest south to southeast winds will continue
as surface high pressure remains over the southeast states and
adjacent Gulf waters. Deep tropical moisture in place will
continue to result in scattered showers and thunderstorms Tuesday
and Wednesday, with rain chances decreasing for the middle and
latter part of the week as mid to upper level ridging builds
aloft.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 73 88 73 91 / 40 60 20 40
LCH 76 88 76 90 / 50 50 10 30
LFT 74 88 75 89 / 50 60 10 40
BPT 77 88 77 90 / 30 40 10 30
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&
$$
PUBLIC...08
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
823 PM CDT Mon Jun 12 2017
.UPDATE...
819 PM CDT
A bit of a tricky forecast through the remainder of the evening with
respect to precip chances, winds, and temperatures. Strong bowing
line of convection continues to push east across Wisconsin to Lake
Michigan while precipitation has been festering along the
southern flank of the cold pool as it sinks south across the
Illinois border. The boundary is pushing into an increasingly
capped boundary layer which can be seen in radar trends with
diminishing convection as outflow pushes south. Cannot rule out
some elevated showers or storms across mainly the northern tier of
counties with very modest southerly low/mid level flow overriding
the boundary, but it would appear the threat for surface based
convection on the leading edge of the cold pool is very low which
will greatly limit the severe threat over northern Illinois this
evening. It does appear there will be sharp wind shift to the
north with gusts to around 30 mph possible along with a rapid
drop in temperatures as the boundary moves across. Temperatures
are expected to fall from the upper 80s/low 90s back into the low
to mid 70s and possibly a few upper 60s. None of the hi-res
models are picking up on this so have had to manually adjust
hourly temperatures and winds based on extrapolation and
eventually blending closer to the ESRL HRRR which shows outflow
spilling inland off of Lake Michigan later tonight, but needless
to say confidence in the details is very low. In addition, how far
south the boundary will push remains a big question mark and will
certainly impact temperatures and convective chances into the day
tomorrow.
Deubelbeiss
&&
.SHORT TERM...
248 PM CDT
Through Tuesday...
Main forecast concerns for this afternoon through tomorrow will be
the continued unseasonably warm weather and chances for showers and
thunderstorms tonight and tomorrow.
For the remainder of this afternoon, mostly sunny, breezy and dry
conditions will continue as a frontal trough and associated weak
cold front extends from the central plains, through central
Wisconsin and Lake Michigan. a moderate southwesterly gradient will
keep winds gusting to 25 mph or so through sunset. Winds should
diminish with sunset and the weak cold front will sag south through
the evening and overnight. Latest guidance suggests that the front
will stall out near the IL/WI border. Frontal convergence and
increasing moisture pooling along the front will likely generate an
area of thunderstorms overnight, but with the boundary expected to
remain north of the border, expect the bulk of the convective
activity to remain north of the CWA, but there is certainly a chance
for some thunderstorms to sag southeast, so have spread chance PoPs
for tsra/shra into the northern tier counties overnight. Some of
the high res model guidance is indicating the formation of a strong
outflow boundary which could track southeast, from swrn WI through
the Chicago metro area late tonight into early tomorrow morning.
While confidence in ts trends for activity over the Chicago metro
area into nwrn IN is low, this scenario is not out of the realm of
possibility, so will carry some slight chance PoPs for tsra/shra
across much of the area, increasing the PoP coverage with time
overnight. Since the airmass will remain warm, expect that lows
tonight will be in the low to some isolated middle 70s overnight.
The forecast for Tuesday has some concerns in the temperature and
precipitation trends. The synoptic pattern will once again support
temperatures to reach into the low 90s again with prevailing swly
flow at the lower levels and upper ridging remaining in place aloft.
The main wildcard will be cloud cover association with any
thunderstorm development tomorrow. With the main sfc low remaining
over the nrn plains and high pressure parked over the sern CONUS,
expect the synoptic front to remain north of the CWA, through
northern Minnesota and central Wisconsin. With a warm, moist air
mass remaining in place, and dewpoints possibly creeping higher to
close to 70F, the environment will be quite unstable. Any
thunderstorm activity will likely focus along old outflow
boundaries. The sfc pressure gradient should also weaken enough for
some lake influence. While a true lake breeze is not expected, with
sfc winds becoming sly arnd 10 mph, winds along the Illinois shore
of Lake Michigan could shift to swly late in the afternoon. This
would have 2 main impacts on the forecast for far nern IL. One,
temperatures along the lakefront could end up being a little lower
and the lake breeze boundary could provide enhanced forcing for more
than isold thunderstorm development. Even for the bigger picture,
there is more uncertainty in the max temperature forecast for the
day, which could be limited if enough debris cloud from decaying
convection hands around the area. Given low confidence in the
smaller scale impacts, residual cloud cover and lake influence, will
make little chance to the going forecast for temperatures, keeping
max temps in the low 90s across all of the CWA with the exception of
the Illinois lakefront. A late-forming lake breeze could limit max
temps there in the low to middle 80s and exact temps will be highly
dependent on the exact timing of the lake breeze pushing inland.
&&
.LONG TERM...
258 PM CDT
Tuesday night through Monday...
The upper level ridge shifts east and zonal flow sets up over the
region. This will allow multiple upper level waves to pass overhead
creating an active extended forecast period. I have concerns about
precip coverage mainly Tuesday night given the recent dry spell, but
it is a good sign that the models are hinting toward multiple
periods of precip.
Did not adjust high temps from SuperBlend. Wednesday and Thursday
could be a couple of degrees warmer than currently forecast, but
have concerns that precipitation and cloud cover may limit heating.
I have low confidence in shower/thunderstorm coverage Tuesday night.
The GFS and NAM feature a weak upper level vorticity streamer that
may produce a bit of lift, and a lake breeze that should be a more
effective lift mechanism. Guidance has CAPE values around 2000 J/kg
and little to no shear. A weak cap is also forecast to form in the
evening. Therefore, the main question is if convection will be able
to overcome any cap that forms. The GFS has much more precip than
the ECMWF and NAM, and since the upper level wave is weakening as it
shifts northeast over the lake, I`m leaning toward the drier models.
As such, kept precip chances to chance or less.
Showers and storms Wednesday look a lot more promising. Guidance
suggests a left over boundary or MCV from convection over Iowa will
help force showers and storms, especially Wednesday afternoon.
Forecast CAPE values are around 2500 J/kg, but as with Tuesday,
shear is only around 20 kt. So can`t rule out a couple of strong
storms with wind or hail, but widespread severe weather is not
expected.
A cold front moves through Thursday, but still expecting high temps
around 90. Any lingering showers push east leading to a dry
afternoon and evening. The active pattern keeps rolling though with
another wave possibly approaching from the west late Thursday night.
The GFS has the wave, while the ECMWF is dry. Decided to keep a
slight chance of showers and storms in the forecast for late
Thursday night.
While guidance differs on exact timing, expecting a chance of
showers and storms every day Friday through Sunday. Temps look to
slowly cool through the late part of this week. A large upper level
trough swings through Sunday and Monday, and it should bring an end
to the near 90 temps. High temps Sunday look to be in the low to mid
80s, and then in the low 80s to upper 70s Monday.
JEE
&&
.CLIMATE...
300 PM CDT
Unseasonably hot conditions will continue early this week. While
the current forecast does not have high temperatures reaching
record highs, readings through Tuesday may be only a couple of
degrees shy of records, especially at Rockford. Below are the
Chicago and Rockford record high temperatures through Tuesday.
Chicago Rockford
Tuesday June 13th 95 1956/1954 94 1987/1976/1956/1921
- NWS Chicago
&&
.AVIATION...
For the 00Z TAFs...
Very low confidence overnight into Tuesday with respect to wind
direction and SHRA/TSRA threat. Cluster of SHRA/TSRA likely to
mainly continue east and remain north of the terminals this
evening, however outflow boundary from this cluster is likely to
sag into N IL later this evening and could latch onto the marine
layer over the lake and accelerate south farther over NE IL/NW
IN. Cannot rule out some isolated showers and perhaps a
thunderstorm developing near the outflow tonight, but in general
conditions look much less favorable this far south in N IL, so
opted to keep the TAFs dry other than a VCSH at RFD tonight.
What happens with winds late tonight into Tuesday is a conundrum.
It is possible that the lake enhanced outflow boundary could hold
its own and keep winds easterly into the day Tues over NE IL and
even at GYY. Conversely, it is possible the boundary could mix out
and winds return to SSW Tuesday morning with just a chance of a
lake breeze wind shift to east in the afternoon. Either scenario
seems very plausible and hard to pick one over the other. Opted to
trend more toward lake influence given the time of year and
thermal differential between the marine layer and land, but
confidence is very low. Additional TSRA could develop Tues
afternoon, especially in the vicinity of the boundary. Not looking
like a strong signal so just opted for a PROB30 for now.
- Izzi
&&
.MARINE...
258 PM CDT
A cold front is over central Lake Michigan and it will continue to
slowly shift south this evening and then dissipate Tuesday. Wind
direction will differ along the lake with northeast to east winds
north of the front and southerly winds south of the front. Winds
become easterly across the lake Tuesday night, and wind speeds will
also be stronger over the northern end of the lake through Tuesday
night.
The next low forms over the plains Tuesday and reaches south central
Canada Wednesday. The low remains stationary through Thursday
morning and then shifts east Thursday afternoon. A cold front will
move over the lake Thursday shifting winds to the southwest.
However, winds become southerly as the low shifts east over Ontario
Friday. A second cold front moves through Saturday/Saturday night.
JEE
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
717 PM CDT Mon Jun 12 2017
.SHORT TERM...(This evening through Tuesday)
Issued at 358 PM CDT Mon Jun 12 2017
Showers and thunderstorms developed across South Dakota and advanced
east through southern and central MN. We still have stratiform rain
lingering behind the main line of thunder which by 4PM local time
has reached the Eau Claire area. The main change with the forecast
from now through the rest of the night is the decreased pops as the
synoptic front has been forced south of our area by todays
acitivity. The HRRR has been relied on most heavily to update this
forecast as much of the guidance (especially global) failed to
capture todays activity.
We could see some showers and thunderstorms overnight move into
western MN as the main upper level low ejects disturbances in the
flow to the northeast. This activity would also be aided by the low
level jet progressing east from the Dakotas toward western MN.
The strong low pressure system currently moving into northern Utah
will continue northeast and lift to eastern Montana by tomorrow
afternoon. A dry line will progress east across the Dakotas and be
the focus of a line of thunderstorms that will develop in a north-
south line across the Dakotas tomorrow afternoon. That activity is
what is expected to quickly progress eastward and impact our area
tomorrow night which is discussed further in the long term section
below.
.LONG TERM...(Tuesday night through Monday)
Issued at 358 PM CDT Mon Jun 12 2017
We`ll stay in this humid and active weather pattern through
Wednesday, before a cold front finally clears out some of the
moisture. We`ll transition to a more zonal pattern this weekend,
with the upper jet shifting south of the MPX area, allowing
temperatures to cool back to normal by the start of next week.
We`ll start this period Tuesday evening with a likely strong to
severe line of storm about ready to cross the border from the
Dakotas into MN. All the CAMs are pretty similar with their
depiction of a line of storms entering MN around 00z and western
WI around 6z, which matches up well with the large scale forcing
seen from the deterministic models. In terms of severe parameters,
ahead of the cold front we will have over 3000 j/kg of MLCAPE
ahead of the cold front. Shear vectors are parallel to the front,
which would favor the development of line segments, so wind then
hail look to be our main threats. The tornado threat looks
greatest in eastern North Dakota to the north of the triple point,
though we cold see that tornado treat bleed into west central MN
along the warm front if we can get discrete cells out ahead of the
line, though that looks unlikely given the degree of capping we
are seeing in the soundings around 700mb.
Going into Wednesday, the question becomes how far east does the
front make it by the afternoon. The GFS/ECMWF have it basically
lined up the I-35 corridor at 18z Wednesday, but the MPAS has it
back to the west of the Twin Cities, so there is still uncertainty
to where the Wednesday convection goes. The majority of models
show convection initiating east of I-35, so this is where our
highest PoPs are. By Wednesday, the front will start to run away
from the parent wave up by Winnipeg, so the height falls and
forcing won`t be as great, with storm coverage expected to be more
scattered. We`ll still have ample CAPE and shear to support a
severe risk and the current SPC Day 3 outlook captures this front
well.
The front that goes through Wednesday looks to make it down into
IA/northern IL on Thursday before it starts creeping back to the
NW on Thursday night, getting back up into the southeast portion
of the MPX CWA Friday afternoon, with thunderstorm chances
returning then. We will have mid and upper level jetting moving
overhead on Friday, so we`ll have plenty of deep shear to support
at least an isolated severe threat then.
Over the weekend into next week, models show a broad upper low
developing across Canada, with the upper jet dropping down across
the northern tier of the CONUS. There will be several shortwaves
swinging through the area in this period, but there is little
model agreement on timing of these waves, so there are lots of
small chances of PoPs through the weekend. What we can confidently
say is the weather pattern will allow temperatures to retreat back
to around normal. There`s low confidence on precip though, with
the GFS/Canadian showing mainly weak and unorganized waves moving
through, while the 12z ECMWF has a couple of well defined surface
lows and deformation precip bands Saturday night and again going
into the middle of next week working through the upper MS Valley.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 717 PM CDT Mon Jun 12 2017
VFR conditions expected through much of the night, with some MVFR
cigs possible toward Tuesday morning. Those cigs should rise by
early afternoon. A few storms may develop overnight along a warm
front, but confidence is low on coverage so left mention out of
all tafs. A better chance for storms will be Tuesday evening.
KMSP...Erratic winds have largely settled and should be light
northeasterly overnight, veering southerly Tuesday and increasing
with some gusts in the 20s by afternoon.
/OUTLOOK FOR KMSP/
Wed...VFR/MVFR with TSRA possible. Wind S-SW 5-10kt.
Thu...VFR. Wind W 5-10kt.
Fri...VFR. Chc MVFR/TSRA. Wind VRB05kt.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...SPD
LONG TERM...MPG
AVIATION...BORGHOFF
Area Forecast Discussion
National Weather Service Marquette MI
821 PM EDT Mon Jun 12 2017
.UPDATE...
Issued at 722 PM EDT MON JUN 12 2017
Main sfc boundary/edge of highest sfc based CAPE over 3000j/kg and
theta-e gradient is well to our south, running west to east across
central WI. Progressive bow echo continues to run along the
boundary producing sporadic wind damage. Cluster of showers and
thunderstorms well to north of main bow is expanding farther north
quickly this evening though (into Marathon county WI) and should
clip at least southern Menominee county starting 2330z-0030z or
730-830 pm ET. Increased pops over southern Menominee county.
Pocket of daytime heating ahead of cirrus blowoff has supported
ribbon of sfc based CAPE over 1000 j/kg and DCAPE nearing 1000j/kg
into southern Menominee county per latest RAP analysis. Based on
this instability and overall look on radar and satellite it is not
out of question that southern portions of Menominee could see
marinal severe wind gusts 45-50 kts this evening. Will continue to
monitor this but for now did add mention of gusty winds for any
thunderstorms in the grids. Some risk of showers and embedded
thunder even making it as far north as IMT and ESC per radar trends
and 21z HRRR output, so brought some slight chance pops in there
after 01z or 9 pm ET.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 233 PM EDT MON JUN 12 2017
Satellite imagery this afternoon shows considerable clear skies
across much of the U.P. along with some marine fog over the eastern
half of Lake Superior. With abundant sunshine and continued mild air
overhead, surface temps have realized the warm layer and pushed into
the mid/upr 70s with a few low 80s showing up across the
south/southwest forecast area. The frontal boundary that had brought
rain/storms Sun ngt has remained displaced to the south, and has not
begun to advect north just yet; however, this feature is progged to
start a northward progression this evening.
Anti-cyclonic surface feature will linger slightly longer this
evening, centered just north of Lake Superior, with the baroclinic
quasi-stationary boundary oriented from Central Minnesota to Central
Lower Michigan. Mid-level heights are beginning to increase across
eastern Dakotas and eventually push east. With the frontal boundary
displaced to the south this evening, the next lobe of vorticity that
was to bring rain/storms tonight will likely continue to slide east
along the boundary and another piece will break to the northwest.
Early Tue the 500mb heights will continue to amplify across the
Upper Midwest and could bring the frontal boundary across the
forecast area during the day, but coverage and intensity of
showers/thunderstorms is not expected to become strong/severe at
this time for Tue. It is possible dry weather could stay in place
for the Northern U.P. and far eastern counties.
Lows tonight will fall into the low/mid 50s, with a few upper 50s
across the southern U.P. Then for Tue highs will warm into the
low/mid 70s, but with a northeast wind areas along the northern U.P.
and adjacent to Lake Superior or within the Lake Superior shadow
could remain several degrees cooler in the upper 50s to low 60s.
.LONG TERM...(Tuesday night through Monday)
Issued at 344 PM EDT MON JUN 12 2017
Late Tuesday night into Wednesday Evening: Little change on overall
thinking from the previous shift on severe weather potential during
this time. MCS development in ND Tuesday evening will track ESE
along the northern periphery of an unstable airmass over the MS
River Valley. Residual activity from this MCS will arrive across the
western CWA and NW WI in the morning, possibly containing some
marginally severe winds. However, severe weather chances Wednesday
afternoon and evening will hinge on if this MCS dissipates before
reaching the area. If that occurs, regeneration of storms is
expected across NE WI and then the central/eastern U.P. within a
modestly unstable airmass under increasing 0-6km shear. Given the
highly conditional nature of this occurring, will continue to only
mention possibilities in the HWO.
Thursday through Saturday: The upper low over south-central Canada
will drift eastward to Quebec while gradually weakening during this
time. Several weak trough axes wrapping around this low will keep
low-end chances of showers and some storms in the forecast. Strong
to marginally severe storms will be possible along lake breeze
convergence zones across the central and east both Thursday and
Friday, though instability will be a limiting factor.
Sunday and Monday: Another mid-level low forming over the northern
Plains on Saturday will shift eastward to far western Quebec on
Monday. Again, showers and possibly a couple storms will be possible
during this time.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 820 PM EDT MON JUN 12 2017
Expect VFR conditions through the TAF period with light winds. Small
chance that showers and embedded thunder over northern WI may graze
SAW late this evening. Also a small chance for showers or
thunderstorms late tonight into Tue morning, especially at IWD. If
there is direct impact from these showers or storms could see
conditions briefly drop to MVFR mainly from vsby.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 233 PM EDT MON JUN 12 2017
Variable onshore winds this evening, decreasing and become light to
less than 10 kt. With high pressure overhead tonight lifting
northeast Tuesday, winds will turn northeast to east but the
gradient is expected to remain light with a 10-20kt winds. Across
the far western arm of Lake Superior winds will be slightly stronger
in the 15 to 25 kt range later in the day Tue.
Across Lake Superior areas of fog to patchy dense fog is showing up
on satellite imagery this afternoon, and looks to continue through
tonight based on forecast data. Have added this into the forecast
through at least Tuesday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
UPDATE...JLA
SHORT TERM...Beachler
LONG TERM...Kluber
AVIATION...JLA
MARINE...Beachler